This invention relates generally to improvements in fuel cell fuel delivery arrangements for use in combustion tools, and more specifically to actuating systems for metering valves used with such fuel cells for delivering the appropriate amount of fuel for use by a combustion tool during the driving of fasteners. While the present application is focused on the use of fuel cells in combustion tools, it is contemplated that other applications are contemplated in which fuel cells or other pressurized containers using stem valves are employed, such as, but not limited to cosmetics and pharmaceutical products.
As exemplified in Nikolich U.S. Pat. Nos. 4,403,722; 4,483,474; 4,522,162 and 5,115,944, all of which are incorporated by reference, it is known to use a dispenser such as a fuel cell to dispense a hydrocarbon fuel to a combustion tool, also known as a combustion gas-powered tool, such as, for example, a combustion gas-powered fastener-driving tool, also known as a combustion nailer. Such fastener-driving tools and such fuel cells are available commercially from ITW-Paslode (a division of Illinois Tool Works, Inc.) of Vernon Hills, Ill., under its IMPULSE trademark. In particular, a fuel cell of this type is described in Nikolich U.S. Pat. No. 5,115,944, listed above.
A design criterion of such fuel cells is that only a desired amount of fuel or dose of fuel should be emitted by the fuel cell for each combustion event. The amount of fuel should be carefully monitored to provide the desired combustion, yet in a fuel-efficient manner to prolong the working life of the fuel cell. Prior attempts to address this dosage factor have resulted in fuel metering valves located in the tool (U.S. Pat. No. 5,263,439) or attached to the fuel cell (U.S. Pat. No. 6,302,297), both of which are also incorporated by reference. Fuel cells have been introduced having internal metering valves, as disclosed in commonly assigned U.S. patent application Ser. No. 10/827,551, filed Apr. 19, 2004, and also incorporated by reference.
Fuel cells configured for use with external metering valves are similar in external appearance to fuel cells having internal metering valves. While adapters are known for improving performance of such combustion nailers (U.S. Pat. No. 6,796,478), and the external fuel cell metering valves of U.S. Pat. No. 6,302,297 are provided with fuel cells upon purchase, through use, it has been known for such adapters and/or valves to become dislodged from the fuel cell, resulting in fuel cells having similar external appearance, but having distinct and incompatible internal performance components.
Regardless of the location of the metering valve, the associated combustion nailer is designed to exert a force on the valve, either the reciprocating valve stem or on the valve body itself, to cause the stem to retract against a biasing force in the metering valve to dispense a measured dose of fuel. Since it is important for fuel economy in the fuel cell, and desired operation of the combustion nailer, for only the designated amount of fuel to be supplied to the tool on a dosage basis, it is also important that users of such tools associate the appropriate type of fuel cell with the appropriate tool and the corresponding metering system. It is also important that the combustion nailer be readily associated with the appropriate fuel cell.
Thus, there is a need for readily distinguishing between combustion tool fuel cells configured for use with external fuel metering valves from fuel cells having internal fuel metering valves.